The proposal is to study humans and cats as they perform maximal jumps with special emphasis on determining the utilization and coordination of muscles involved in the task. This study was chosen because of its close relation to locomotion, the great similarity between humans and cats with respect to the task and the ease with which analytical and experimental techniques can be combined to enhance the understanding of the movement. A simplified optimal control model of the jumping cat has already been developed and solved. This model will be improved, modified to simulate humans jumping and compared with experimental measurements of external forces, limb trajectories and electromyograms. Such analysis will result in a quantitative, as well as qualitative, understanding of maximal jumps in both species. These results will add to the understanding of the coordination of hindlimbs during intact animal movement and facilitate the further study of normal movement in mammals, including man.